UPPER FRANKLIN TRAIL Construction Proposal
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UPPER FRANKLIN TRAIL Construction Proposal January 4, 2017 For: John “Pancho” Smith, Santa Barbara District Ranger Los Padres National Forest Submitted By: Ray Ford, Project Manager Mike Smith, Project Manager Santa Barbara County Trails Council Los Padres Forest Association I. OVERVIEW The Santa Barbara County Trails Council (SBCTC) proposes to restore a 2.69-mile section of the upper Franklin Trail, onto and across land under the management of the Los Padres National Forest (LPNF). The proposed trail would extend from the Phase II section of the lower trail on Santa Barbara County land to the crest of the Santa Ynez Mountains. The purpose of the proposed project is to make improvements to a section of the historic Franklin Trail that is currently inaccessible to the public. The proposed project would increase recreational opportunities for a wide range of trail users to the upper Santa Ynez River watershed and connectivity to existing trails in the Santa Barbara backcountry. It should be noted that restoration of the Franklin Trail poses unique challenges given the steep topography and larger-than-usual portions of the trail that far exceed Forest Service standards for grade. While the underlying bedrock and associated soils have shown to resist erosion over the hundred year existence of the trail, careful use of the sustainable-use techniques described below, best management practices for reducing sedimentation as shown in Appendix A and their specific application by severity of grade as shown in Appendix B should be sufficient to mitigate for excessive grade and minimize erosion such that it meets Forest Service standards. For more detailed descriptions of any of the trail construction guidelines described below please refer to the “Trail Assessment & Analysis For Phase III of the Franklin Trail.” II. TRAIL CONSTRUCTION GUIDELINES Trail construction will use established Forest Service guidelines as described in the “Trail Construction and Maintenance Notebook, 2007 Edition” in restoration of the Franklin Trail. The goal of the project is to provide for safe and sustainable multi-use for hikers, backpackers, mountain bikers, trail runners and equestrians among others. A. Trail Corridor Improvements (See Figure 1 below). Brush will be cleared on either side of the trail centerline to a to create a corridor width ranging of from 6-8 feet and a height of 10 feet depending on side slope steepness and the need to increase the sightlines (amount of distance uphill and downhill users can see one another). Typical cross-section of a trail that meets Forest Service standards for a pack-and-saddle trail. Tread and corridor widths will vary for different grades and sideslopes. 2 (corridor continued) As needed, and especially on side slopes in excess of 30%, the outside brush may not be cut back as much while the uphill side slope brush may be cleared further uphill. Along steeper slopes, vegetation can help maintain the outside edge of the trail while clearing uphill brush hanging over the trail will minimize the need to brush the trail as often. In either case the goal is to maintain the trail corridor to a total width of no more than 8 feet and provides sufficient distance for users to see one another. B. Tread Restoration The Franklin Trail will be constructed to U.S. Forest Service Class 3 Pack-and-Saddle trail width standards with special consideration for sections of the trail with the grades steeper than 8% and/or sideslopes in excess of 30% to achieve expectations for long-term safety and sustainability. As noted above, large portions of the Franklin Trail far exceed Forest Service standards for grade of 3-12% with many sections over 20% and some in excess of 30%. The project proposes the following to provide safe multi-use: • Up to 8% Grade (Non-Wilderness Single Lane Standard): 18” – 48” wide tread (with widths of 48” – 60” where sideslopes exceed 30%) • 9-19% (Non-Wilderness Single Lane Standard): 36 – 48” wide tread, with provision for short passing lanes of up to 60” wide where sideslopes exceed 30% • 20% +: (Non-Wilderness Double Lane Standard): 48 – 60” wide tread to accommodate passing lanes of up to 60” wide and sideslopes exceed 30% C. Erosion Control (See Figures 5 & 6). One of the basic principles of trail construction is that they be sustainable, meaning that they will last over time with a minimum of maintenance. A key component of sustainability is erosion control and the key part of that is to get the water off the trail as soon as possible and to keep it from continuing down the trail for any distance. Restoration of the Franklin Trail poses unique challenges given the topography and larger-than- usual portions of the trail that exceed Forest Service standards. While the underlying bedrock and associated soils have shown to resist erosion over the hundred year existence of the trail, careful use of the sustainable-use techniques described below, best management practices for reducing sedimentation as shown in Appendix A and their specific application by severity of grade as shown in Appendix B should be sufficient to mitigate for excessive grade and minimize erosion such that it meets Forest Service standards. The project proposes use of the following measures to ensure sustainability: Brush and Fill. The technique involves lining the lower edge of the trail with brush, chainsawing it into fine pieces and then filling it with the slough material cleared from the lower backslope. This serves to act as a sedimentation barrier that prevents erosion, traps any soil being carried off the trail and makes valuable use both of the brush and backslope material. Outsloping. Outsloping (sloping the tread away from the hillside) is one of the key concepts used to eliminate the impacts caused by running water. The project proposes to outslope the trail in amounts ranging from 5-7% wherever possible, with slightly higher percents (8-9%) where the 3 trail grade is steeper. Slightly increasing outslope, along with armoring edge armoring (see below), can be very effective in mitigating for grade. Armoring the Trail. In areas where the outside edge of the trail is less stable, use of nearby rock material will be embedded to further stabilize trail edge. Used in conjunction with outsloping, this not only protects the outer edge from user damage, but also will serve to reduce erosion. Use of outsloping, brush and fill techniques and armoring works extremely well to meet several key basics: Sheets water off the trail, which is critical in offsetting the potential damage that can be done when water runs down steep sections of trail such as those found along the Phase III section of the Franklin Trail. Makes good use of the brush and slough removed when widening the inner part of the tread. Reduces sedimentation by catching soil that might wash off the trail. Adds a protective barrier on the trail edge to resist gullying, maintain the edge and reduce the impacts from trail use. Rock “Stacking”. The phrase comes from the concept used by those who originally built the Franklin Trail, though they might not have used this term. In constructing the trail, it appears they realized that they could stabilize the outer edge of the trail simply by using the rock pried up when they were removing rock and soil to create the tread. The project proposes use of this technique wherever there is a large supply of rock, loosely stacking it below the lower edge of the trail to lightly armor the slope. Use of Grade Reversals. Designing grade reversals into an existing trail presents challenges, especially on trails contouring along a steep hillside where it isn’t that easy to add rises and falls without extensive backsloping and creating the potential to destabilizing the hillside. However, even on steep trails like the Franklin, it is possible to add grade reversals at key points above and in the middle of many of the steeper sections where there are short level areas. The goal is to divert water off the trail above any steep section and in the middle of it wherever there is enough relatively level tread to build them. Addition of Rolling Drain Dips (Super-Charged Trail Knicks). Rolling drain dips are achieved by removing soil to create a dip in the trail where water can be diverted off it. True dips are much longer, typically constructed with a gentle drop into the dip, a level section and the followed by a gentle rise out of the dip, creating the effect of a grade reversal in locations where reversals aren’t practical. In contrast, the rolling drain dips are relatively short, serve to get water off the trail like water bars were designed to do, but do it more effectively and requiring much less maintenance over time. Rolling drain dips that work well to get water off the trail, minimize the need for maintenance and reduce sedimentation — especially on steeper grades — have a number of characteristics: Use of changes in trail direction. Dips work extremely well at any location where there is a turn in the trail. Water by its nature wants to flow in a straight line. Adding dips where the trail is 4 changing direction aligns the water flow with the direction you want it to go off the trail and reduces opportunities for the dip to become clogged with sediments. Use of rock armoring at the lower edge and bottom of the dip will reduce damage to the dip, protect the lower part of the dip during high water flows and can help slow the water down so sediments are left on the hillside rather than washing downhill into the creeks.